Definitely get in with a club to do Ma Bell...it's a highly 'politically' problem right now. Locals want it shut down, private land owners around it don't want anyone using 'bypasses' and one entire end of it has been shut off. Overused...clubs show up with 20-30 rigs at a time coming from all over New England. I went there couple of years ago with a group of Rubicons...and we had all kinds of trouble on it...even with lockers. You need winch, lift, aggressive tires...and we counted at one point we were in line behind about FIFTY other jeeps and rock crawlers...made for an extremely long and not productive day. I'll never do it again...just not worth it with that many other people waiting to try something. Hardcore rockcrawlers....have all the fun you want. Stock vehicles...forget it!
I have seen stock YJ's with only a front locker succesfully navigate the entire length of open trail this place has to offer. There were a few open-open jeeps who made it as well. We even had a newer FJ that was stock make it all the way up. every obstacle has a viable alternative route for lesser modified vehicles. But... as others have said, this place tends to be packed and over populated.